3D biomes generating in the overworld doesn't match vanilla behavior.

What behaviour is expected:

That the vertical biome placement in the overworld would match that generated with a vanilla client.

What behaviour is observed:

Vertical biome placement on some biome edges changes unlike in vanilla.

Steps/models to reproduce:

This may include a build schematic, a video, or detailed instructions to help reconstruct the issue
Generate a world with a vanilla client and find a mushroom fields island. When the biome changes from mushroom fields shore to ocean, move vertically and it will stay the same. Go to the same coordinates on a paper server with the same seed and the biome will change as you move up and down.

Plugin list:

A list of your plugins
Reproduced with no installed plugins.

Paper version:

Paste the output of running /version on your server WITH the Minecraft version. latest is not a version; we require the output of /version so we can properly track down the issue.

git-Paper-298 (MC: 1.16.4) (Implementing API version 1.16.4-R0.1-SNAPSHOT)
(I updated yesterday but the issue exists with a version I used a few months ago to generate my live server as well.)

Anything else:

Anything else you think may help us resolve the problem

Server logs when generating a fresh world and logging in.
https://logs.panel.gg/01a7a54a3a26f665d41736c7cc51bea7

Vanilla client on the server with F3 open.
https://youtu.be/Lzo_Lr5AxEo

Vanilla client in singleplayer with the same seed and F3 open.
https://youtu.be/l1T4Rv32iGE

Client logs.
https://paste.ee/p/pN0uR

No source file, test, or seed is named. Start by following the mushroom-fields shore reproduction steps and comparing vertical biome results between vanilla and Paper, using the linked videos and logs for reference. Done means Paper's overworld biome placement matches vanilla at the reported biome edge.